Demulsifying process



nnMULsmYlNG rnocnss Willard H. Kirkpatrick, Sugar Land, and Alice Walker, Houston, Tex., assignors to Visco Products Company, Houston, Tex, a corporation of Delaware No Drawing. Application June 22, 1054 Serial No. 438,624

9 Claims. (Cl. 252-340 This invention relates in particular to the treatment of emulsions of mineral oil and water, such as petroleum emulsions commonly encountered in the production, handling and refining of crude mineral oil, for the purpose of separating the oil from the water. Also, the invention relates to the treatment of other water-in-oil types of emulsions wherein the emulsions are produced artificially or naturally and the resolution of the emulsions presents a problem of recovery or disposal.

This application is a continuation-in-part of our application Serial No. 187,824, filed September 30, 1950, now abandoned.

Petroleum emulsions are in general of the water-inoil type wherein the oil acts as a continuous phase for the dispersal of finely divided particles of naturally occurring waters or brines. These emulsions are often extremely stable and will not resolve on long standing. It is to be understood that water-in-oil emulsions may occur artificially resulting from any one or more of numerous operations encountered in various industries. The emulsions obtained from producing wells and from the bottom of States Patent crude oil storage tanks are commonly referred to as cut operation corrosion inhibited acid is forced down the well and into the formation under pressure. The acid attacks limestone formation enlarging the fissures and openings through which the oil fluids flow to the well po'ol, thus increasing the production. In many cases, particularly troublesome emulsions are encountered immediately after a well has been acidized. This condition can be minimized and many times eliminated by incorporating a suitable demulsifying composition with the acidizing medium.

Still another type of process involves the use. of a demulsifying agent of thekind hereinafter described in refinery desalting operations. In the refining of many crude oils a desalting operation is necessary in order to prevent the accumulation of large deposits of salt in the stills and to prevent corrosion resulting from the decomposition of such salts under high still temperatures. In

a typical desalting installation 5% to 10% of fresh water This operation temperaturefor 4 hours. acomposition known in the trade as Ucon 50-HB-660 One object of our invention is to provide a novel and economical process for resolving emulsions of the character referred to into their component parts of oil and water or brine.

Another object is to provide a novel reagent whlch is water-wettable, interfacial and surface-active in order to enable its use as a demulsifier or for such uses where surface-active characteristics are necessary or desirable.-

The compositions of the present invention are reaction products of castor oil, an organic dicarboxy acid and a polyoxyalkylene compound having a molecular weight of at least 1700 which may be either a glycol or a monoether of a glycol and in which the oxyalkylene groups consist essentially of oxyethylene and oxypropylene groups (e. g., oxy-1,2-propylene) wherein the weight ratio of oxyethylene to oxypropylene is at least 1:4 and does not exceed 4:1.

The order of the reactions does not appear to be important but it is usually preferable to react the castor should'be at least 1:3 and the molar ratio of the poly-..

oxyalkylene compound to castor oil likewise should be at least 1:3.

The temperatures of reaction will normally be within the range of 150 C. to 300 C.

The reaction is preferably carried out sufficiently long to eliminate the major proportion of the water formed at the reaction temperatures but short of the formation of a solid gel.

The reaction products have a relatively high molecular weight. For the best results in breaking petroleum emulsions polyoxyalkylene compounds having a molecular weight within the range from about 1700 to about 7500 have been employed in preparing the desired products.

It has been discovered that these compositions have unusual and unexpected properties for resolving waterin-oil emulsions into their component parts. One possible theory which may be postulated for the striking effectiveness of. these compositions in resolving petroleum emulsions is hydrophobe-hydrophile balance which has not been secured heretofore with compositions well known in this art.

factory procedures for preparing a few of the materials suitable for employment within invention; 7

the scope of-thepresent EXAMPLE 1' i V In a suitable reaction vessel there was introduced 448 0,

parts'of castor oil and 950 parts of technical diglycolic acid. The temperature was raised with agitation until' an aqueous distillate began to form at a temperature of about 150 C. The heating was continued until 166 parts of an aqueous distillate had been secured at a maximum temperature of ab out'l70 C. 'The reaction mass was then cooled to C. and condensed at this Approximately 5400 parts of and about 1080 parts of a suitable hydrocarbon fraction such as S0 extract were added to the above intermediate. Ucon 50-HB-660'is the monobutyl ether of a heteric polyoxyalkylene glycol, the polyoxyalkylene chain of which contains ethylene oxide and propylene oxide v 'lsatentedJuly 1,1958,

in a l to 1 ratio, the molecular weight of the monoether being approximately 1700. After the addition of these materials the temperature oi' -the reaction mass is gradually increased until a second aqueous distillate began to form. The heating was continued until a total of about 42 parts of aqueous distillate was secured. The formation of the distillate began at approximately 185 C. and. the required amount was secured at a maximum temperature of about 230 C. After cooling'to approximat ly 140 C., 2880 parts of a suitable hydrocarbon fraction was added and agitated for 45 minutes to yield the finished product.

EXAMPLE II In a suitable reaction vessel 930 parts of castor oil and 201 parts of technical diglycolic acid were heated until 36 parts of an aqueous distillate had been secured. After the aqueous distillate was secured the reaction mass was permitted to condense an additional 2hours at 120 C. To 220 parts of. this intermediate. there was added 170 parts of Ucon 50-HB-660 and 50 parts of a suitable hydrocarbon fraction such as S extract. The mixture was then heated with agitation and at approximately 218 C. an aqueous distillate began to form and heating was continued until approximately 2 parts of aqueous distillate was secured at a maximum tempera-. ture of 253 C. The mass was cooled to 140 C. and 400 parts of S0 extract added with agitation to yield the finished product.

EXAMPLE Il I In a suitable reaction vessel provided with means of agitation, heating and removal of aqueous distillate with simultaneous return of azeotropic distillate to the reaction mass there was added 630 parts of castor oil and 148 parts of phthalic anhydride. These materials were heated and condensed for 7 hours at a temperature of 140 to 155 C. To 250 parts of this intermediate there was added 250 parts of Ucon 50-HB-660 and 50 parts of S0 extract. The reaction mass was heated to 220 C. An aqueous distillate began to form and heating was continued for 2 hours at a maximum temperature of 258 C. Approximately 3 parts of aqueous distillate was secured under these conditions. cooled to 140 C. and about 660 parts of SO extract was added with stirring to yield the finished product.

EXAMPLE IV of the above intermediate there was added 500 parts of Ucon 50-HB-5100 and 100 parts of S0 extract. Ucon 50i-135 100 is a monobutyl ether of a heteric polyoxyalkylene glycol in which ethylene oxide and propylene oxide are present in a ratio of 1:1 and the molecular weight is approximately 5000. The reaction mixture was heated with agitation and at 197 C. an aqueous distillate began to form and heating was continued until a total of 2.2 parts of aqueous distillate had been secured at a maximum temperature of 245 C. The reaction mass was cooled to approximately 140 C. and 1325 parts of S0 extract was added with agitation to yield the finished product.

EXAMPLE V Under similar conditions described in Example III, 315 parts of castor oil and 67 parts of technical diglycolic acid were heated to, secure 9.; parts. Of an aqueous.

The reaction mass was distillate. This reaction required approximately minutes at a temperature of l 62 to 180 C. The heat was then lowered to 150 C. and condensation permitted to occur at this temperature for an additional 5 hours. To parts of this intermediate there was added parts of Ucon 75-H-1400 and 50 parts of S0 extract. Ucon 75H1400 is a heteric polyoxyalkylene glycol in which the ethylene oxide to propylene oxide ratio is 3:1 and the molecular weight is approximately 2200. These reactants were heated over the range from 197 C. to 240 C. during which 1.1 parts of aqueous distillate was secured. The reaction mass was cooled to approximately C. and 325 parts of S0 extract added with stirring to yield the finished product.

EXAMPLE VI Under conditions similar to those described in Example III, 189. parts of castor oil and 40 parts of technical digylcolic acid were heated to lose 7.2 parts of an aqueous distillate. This reaction required approximately 3.5 hours at an initial temperature of 140 C. and a maximum temperature of 228 there was added 370 parts'of Ucon 25-HDG and 50 parts of S0 extract. Ucon ZS-HDG is a heteric polyoxyalkylene glycol having an ethylene oxide to propylene oxide ratio of 1:3 and a molecular weight of 3700. These reactants were heated for approximately 0.5 hour between 220 C. and 250 C. During this interval 1.9 parts of aqueous distillate were secured. The reaction mass was cooled to approximately 140 C. and 300 parts of S0 extract were added to yield the finished product.

In the foregoing examples, the quantities are given in parts by Weight. Within the limits previously defined, any of the diols described in U. S. Patent 2,425,845 and any of the monoethers described in U. S. Patent 2,448,664 may be substituted for the respective diols and monoethers in the foregoing examples.

By way of illustrating the remarkable effectiveness of the products contemplated by this invention, the method of testing their efliciency in bottle tests will be described and exemplary data given, and this will be followed by the results of a full scale plant test.

Field bottle test I State of Arkansas.

Oil field Smart. Oil company R. H. Crow Drilling. Lease Taylor. Well B-l. Percent emulsion in fluid from the well 65. Percent water in the fluid from the well 0. Percent water obtained by complete demulsification.. 54. Temperature of test F. Manual agitation A hot shakes' 200 cold shakes.

Treating ration, 1/5,000.

One hundred (-100) cc. samples of the emulsion were .taken and placed in conventional .field test bottles.

' additional 50 times at a treating temperature of 150 F.

Aftershaking in each instance the water-drop was determined-and recorded, that is to say, the amountof water" whichfseparated from the emulsion. The color of'the oil was. also observed and recorded at the same time. After agitation at elevated temperature, the samples Were maintained at 150 F. for a total of 60 min, utes to permit settling and Stratification of the water.

C. To this intermediate 'The emulsion sample'was secured just after the 'oil came from the well and every ,efiort was made .to maintain conditions comparable to those present in a full scale plant treatment. After agitation the samples were allowed to settle and were tested for water-drop at predetermined periods of time and recorded on suitable test sheets. The test showed that the composition as prepared in accordance with instructions of Example II released 27 parts of water after cold agitation. After the bottles had reached treating temperature of 150 F. the composition of Examplell had dropped 50 parts of water and after standing 60 minutes at treating temperature the water-drop increased slightly. The color of the oil using Example 11 composition was excellent. The treated oil contained no residual emulsion whereas the chemical being used commercially in the plant systemshowed 1.2 parts of emulsion remaining which had not been resolved.

Field bot tle test 11 State of Texas. Oil field Forsan. Oil company Continental. Lease Eason. Well No. 1.

Percent emulsion in fluid from the well- 55. Percent water in the fluid from the well 10. Percent water obtained by complete demulsification 43. 7 Temperature of test Atmospheric. Manual agitation 200 cold shakes. Treating ratio 1/ 33,300.

Using the procedure similar to that described in Field Bottle Test I, without treating with external heat, tests were made with compositions as prepared in Examples I and 11. Both gave good color to the resolved oil which indicated substantial resolution. At the indicated treating ratio, Examples I and II compositions dropped approximately 25 parts of the recoverable water after standing 10 minutes. After 20 minutes standing approximately 35 parts of water had separated. Upon addiditional standing, substantially all of the recoverable water had separated. The treated oil with Examples I and II compositions met pipeline specifications and could be successfully used in commercial scale operations.

Field bottle test 111 State of Arkansas. Oil field Shuler.

Oil company Lion. Lease C.

Wells No. 16, 17.

Percent emulsion in fluid from the well 60. Percent water in the fluid from the well 4. Percent Water obtained by complete de- Using the procedure similar to that described in field bottle test I, tests were made using compositions as prepared in Examples I and II. Both gave excellent color to the resolved oil indicating substantial breaking of the emulsion. After 10 minutes at treating temperature of 140 F. 20 parts of water had stratified and upon standing an additional 20 minutes all of the water had Stratified and the treated oil showed trace or less emulsion and water present. Under identical conditions, the chemical being used commercially dropped only 5 parts of water after 10 minutes standing and 35 parts after an additional 20 minutes standing. The oil layer with this chemical contained 16% emulsion and 1.2% water.

Field plan't scale test This test was made by actually treating the oil coming from the well described in field bottle test III. A National heater treater was being used witha chemical proportioning pump to add the chemical treating reagent. 7 .1

The treating agent employed was prepared in accordance with the directions of Example II. The plant test was started at'8z'00 a: m. and was observed continuously until 1:00p. m. of the following day. During this plant test an average of 26 pints of chemical-was used during a 24 hour period. In this 24 hour period 1200 barrels of substantially dry oil were produced. During this test thetreated oil met pipeline specifications and averaged less than 2% emulsion and water. Observations made during this plant test indicatedthatan excess amount of chemical had been used and subsequent plant tests demonstrated that this oil could-be treated using as'little as 12 pints of chemical per 24 hours which is a treating ratio of 800barrels of net oil per gallon of chemical.

The treating ratio with the commercial chemical used previouslywas 1 gallon'of chemical to 300 barrels of net oil; I

The demulsifying compositions are preferably employed in the proportion of 1 part of reagent to from 2000 to 50,000 parts of emulsion either by adding the concentratcd product direct to the emulsion-or after diluting with a suitable vehicle in the customary manner.

The suitable hydrocarbon vehicle referred to in the examples is sulfur dioxide (S03) extract. This material is a by-product from the Edeleanu process of refining petroleum in which the undesirable fractions are removed by extraction with liquid sulfur dioxide. After removal of the sulfur dioxide a mixture of hydrocarbons, s'ubstantially aromatic in character, remains which is designated'in' the trade as S0 extract. Examples of other suitable hydrocarbon vehicles are Gray Tower. polymers, toluene, xylene, gasfoil, diesel fuel, bunker fuel. The above cited examples of.

and coal tar solvents, solventsare adaptable to azeotropic distillation as would also be any other solvent which is immiscible with water, miscible with the reacting mass and has a boilthe dicarboxy acids and their anhydrides which hydrolyze to the acid in the presence of water, e. g., digylcolic acid, phthalic acid, phthalic anhydride, maleic acid, maleic anhydride, succinic acid, malic acid, adipic acid an homologues thereof.

The invention is hereby claimed as follows; 1. A process of breaking water-in-oil emulsions which comprises treating such emulsions with the product of the reaction of castor oil, an organic-dicarboxy'acid and a polyoxyalkylene compound having a molecular Weight of at least 1700 from the group consisting of glycols and monoethers of glycols in which the oxyalkylene groups consist essentially of oxyethylene and oxypropylene groups and the weight ratio of oxyethylene to oxypropylene is at least 1:4 and not greater than 4:1,"

said reaction being efiected at 150 C; to 300 C. with the elimination of not more than the usual water of esterification required to form simple esters.

2. A process of breaking water-in-oil emulsions'which comprises treating such emulsions with the product of essentially of oxyethylene and oxypropylene groups and the weight ratio of oxyethylene to oxypropylene is at least 1:4 and not greater than 4:1, said reaction being effected at 150 C. to 300 C. with the elimination of not more than the usual Water of esterification required to form simple esters.

3. A process of breaking Water-in-oil emulsions which comprises treating such emulsions with the product of the reaction of castor oil, an organic dicarboxy acid and a polyoxyalkylene glycol monoether having a molecular weight of at least 1700 in which the oxyalkylene groups consist essentially of oxyethylene and oxypropylene groups and the weight ratio of oxyethylene to oxypropylene is at least 1:4 and not greater than 4: 1, said reaction being efiected at 150 C. to 300 C. with the elimination of not more than the usual Water of esterification required to form simple esters.

4. A process of breaking water-in-oil emulsions which comprises treating such emulsions with the product of the reaction of castor oil, diglycolic acid and a polyoxyalkylene ompound h g a mol cular. Weigh f at least 1700 from the group consisting of glycols and monoethers of glycols in which the oxyalkylene groups consist essentially of oxyethylene and oxypropylene groups and the weight ratio of oxyethylene to OXYPropylone is at least 1:4 and not greater than 4:1, said reaction being effected at 150 C. to 300 C. with the elimination of not more than the usual water of esterification required to form simple esters.

5. A process of breaking water-in -oil emulsions which comprises treating such emulsions with the product of the reaction of castor oil, diglycolic acid and a polyoxyalkylene glycol having a molecular weight of at least 1700 in which the oxyalkylene groups consist essentially of oxyethylene and oxypropylene groups andthe Weight ratio of oxyethylene to oxypropylen is at least 1:4 and not greater than 4: 1, said reaction being effected at 150 C. to 300 C. with the elimination of not more than the usual water of esterification required to form simple esters.

6. A process of breaking-in-oil emulsions which comprises treating such emulsions with the product of the reaction of castor oil, diglycolic acid and a polyoxyalkylene glycol monoether having a molecular weight of at least 1700 in which the oxyalkylene groups consist essentially of oxyethylene and oxypropylene groups and the weight ratio of oxyethylene to oxypropylene is at least 5 1:4 and not greater than 4:1, said reaction being efiected at C. to 300 C. with the elimination of not more than the usual water of esterification required to form simple esters.

7. A process of breaking water-in-oil emulsions which comprises treating such emulsions with the product of the reaction of castor oil, an organic dicarboxy acid and a polyoxyalkylene compound from the group consisting of glycols and monoethers of glycols in which the oxyalkylene groups consist essentially of oxyethylene and oxypropylene groups and the weight ratio of oxyethylcue to oxypropylene is at least 1:4 and not greater than 4:1, the molecular weight of said polyoxyalkylene compound being within the range from 1700 to 7500, said reaction being efiected at 150 C. to 300 C. with the elimination of not more than the usual Water of esterification required to form simple esters.

8. A process of breaking water-in-oil emulsions which comprises treating such emulsions with the product of the reaction of castor oil, an organic dicarboxy acid and a monoether of a polyoxyalkylene glycol in which the oxyalkylene groups consist essentially of oxyethylene and oxypropylene groups and the weight ratio of oxyethylene to oxypropylene is at least 1:4 and not greater than 4:1, the molecular weight of said polyoxyalkylene glycol monoether being within the range from 1700 to 7500, said reaction being effected at 150 C. to 300 C. with the elimination of not more than the usual Water of esterification required to form simple esters.

9. A process of breaking water-in-oil emulsions which comprises treating such emulsions with the product of the reaction of castor oil, an organic dicarboxy acid and a monoether of a polyoxyalkylene glycol in which the oxyalkylene groups consist essentially of oxyethylene and oxypropylene groups and the weight ratio of oxyethylene to oxypropylene is at least 1:4 and not greater than 4:1, the molecular weight of said polyoxyalkylene glycol being within the range from 1700 to 7500, said reaction being efiected at 150 C. to 300 C. with the elimination of not more than the usual water of esterification required to form simple esters.

References Cited in the file of this patent UNITED STATES PATENTS 2,442,073 De Groote et al May 25, 1948 2,505,824 De Groote et al. May 2, 1950 2,679,521 De Groote May 25, 1954 

1. A PROCESS OF BREAKING WATER-IN-OIL EMULSIONS WHICH COMPRISES TREATING SUCH EMULSIONS WITH THE PRODUCT OF THE REACTION OF CASTOR OIL, AN ORGANIC DICARBOXY ACID AND A POLYOXYALKYLENE COMPOUND HAVING A MOLECULAR WEIGHT OF AT LEAST 1700 FROM THE GROUP CONSISTING OF GLYCOLS AND MONOETHERS OF GLYCOLS IN WHICH THE OXYALYLENE GROUPS CONSIST ESSENTIALLY OF OXYETHYLENE AND OXYPROPYLENE GROUPS AND THE WEIGHT RATIO OF OXYETHYLENE TO OXYPROPYLENE IS AT LEAST 1:4 AND NOT GREATER THAN 4:1, SAID REACTION BEING EFFECTED AT 150*C. TO 300*C. WITH THE ELIMINATION OF NOT MORE THAN THE USUAL WATER OF ESTERIFICATION REQUIRED TO FORM SIMPLE ESTERS. 